This project involves digital processing and computer interpretation in electrocardiography (ECG), which is the most widely used diagnostic and prognostic tool in cardiovascular disease including ECG monitors, ambulatory ECGs, signal-averaged ECGs, and exercise ECGs. In the U.S. up to 150 million routine diagnostic ECGs are performed annually. The ambulatory ECG and the signal-averaged ECG are used to estimate risk of sudden death from fatal cardiac rhythm disturbances. The exercise ECG is used to diagnose coronary disease. A particularly useful application of ECG is the determination heart rate variability (HRV), an index of autonomic nervous system influence upon the heart. Also in FY02, a follow-up study in the long term collaboration with Children's National Medical Center of HRV in syncopal patients is in publication. In collaboration with NHLBI; the Agency for Health Care Policy and Research; and the Minnesota Heart Institute Foundation a meta-analysis of data for different diagnostic modalities such as HRV, signal-average ECGs, frequent ventricular beats and ejection fraction has been performed to compare their prognostic power after myocardial infarction; the manuscript was published. Follow-up research on sudden cardiac death was pursued in collaboration with the Minnesota Heart Institute and the University of Minnesota School of Public Health, which has resulted in papers and abstracts published in the Journal of Electrocardiology and Circulation. In collaboration with several members of previous AHA Committees on electrocardiography, a report re-establishing AHA electrical safety standards for electrocardiographs has been published. J. Bailey chairs the ECG Committee for the Association for Advancement of Medical Instrumentation supervising six working groups (subcommittees) dealing with national and international medical device standards. One more standards document was published this year. J. Bailey was appointed to the editorial Board for the Journal of Electrocardiology.